LONDON (Reuters) - British counter-terrorism officers stopped a plane as it taxied towards the runway at Heathrow to prevent a 15-year old girl from travelling to Syria to join Islamist fighters, the Evening Standard newspaper said on Wednesday.

The girl, from east London, had saved up and bought a ticket to Istanbul without her parents’ knowledge, the paper said.

She was removed from the flight and has since returned home but another girl, also aged 15, who was taken off the plane with her, managed to leave before police could intervene, it added.

Asked about the report, police said they had received reports about a girl missing from Tower Hamlets on Dec. 6.

“Officers were able to locate her and she has since returned home safely,” a spokeswoman said, without elaborating.

No further details were immediately available.

A British Airways spokeswoman confirmed that one of its flights to Istanbul had had to turn back on Dec. 6.

“There was a flight that had to turn back because two passengers were removed from the plane,” she said.

Officials estimate that over 500 British citizens have travelled to Syria, where the Islamic State group has seized large swathes of territory, and London’s police chief Bernard Hogan-Howe has said some 250 have since returned.

Prime Minister David Cameron has warned that returning militants could launch attacks at home.